Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!ucsd!helios.ee.lbl.gov!hellgate.utah.edu!uplherc!esunix!bgeer
From: bgeer@esunix.UUCP (Bob Geer)
Newsgroups: comp.lang.pascal
Subject: Re: Findfirst
Message-ID: <2075@esunix.UUCP>
Date: 20 Jul 90 13:18:57 GMT
References: <1990Jul13.232754.29083@dhw68k.cts.com>
Organization: Evans & Sutherland, Salt Lake City, Utah
Lines: 72
X-Local-Date: 20 Jul 90 06:18:57 PDT

From article <1990Jul13.232754.29083@dhw68k.cts.com>, by silk@dhw68k.cts.com (Mitch Gorman):
> In article <23854@adm.BRL.MIL> elric%FSU@pucc.princeton.edu (Commodore 128 User) writes:
>> You need to have it search for 'archive' type files.  [...]
>... 
> 	The smart way to do this, guaranteed to find any and all honest-to-god
> files, is "findfirst(..., anyfile - directory - volumeid, ...);".  
> 

Back in the Turbo Pascal 1 & DOS 2 days I wrote a directory browser
using DOS software interrupt calls since there was no "findfirst()"
library procedure.  I have listed below the file attribute byte
breakdown, a code fragment that searches for either all files or
non-hidden, non-system files (volume label & sub-dirs were handled
specially), and the breakdown of the FCB & DTA records, that resulted
from that experience.  Hopefully seeing this stuff will shed some
light on directory searches from within a program.

BG -- Bear-person

_______________________________________________________________________________
CONST
  READ_ONLY       = $01   ; { file attribute byte map }
  HIDDEN          = $02   ; { " }
  SYSTEM          = $04   ; { " }
  VOLUME_LABEL    = $08   ; { " }
  SUB_DIRECTORY   = $10   ; { " }
  ARCHIVE         = $20   ; { " }

  VAR { local }
     attributes : BYTE ;

  IF write_all_files THEN
     attributes := $FF - VOLUME_LABEL - SUB_DIRECTORY { everything! }
     {attributes := ARCHIVE + READ_ONLY + SYSTEM + HIDDEN}
     ELSE
     attributes := ARCHIVE + READ_ONLY ;

TYPE
  FCB_RECORD       = RECORD { used by DOS 1.x filing calls }
                     extended_fcb_flag  : BYTE ;
                     unused1            : ARRAY [2..6] OF BYTE ;
                     attribute          : BYTE ;
                     fcb_drive_number   : BYTE ;
                     file_name          : ARRAY [1..8]  OF BYTE ;
                     extension          : ARRAY [9..11] OF BYTE ;
                     block_number       : INTEGER ;
                     record_size        : INTEGER ;
                     low_size           : INTEGER ;
                     high_size          : INTEGER ;
                     created_date       : INTEGER ;
                     reserved1          : ARRAY [22..31] OF BYTE ;
                     seq_record_no      : BYTE ;
                     low_ran_record_no  : INTEGER ;
                     high_ran_record_no : INTEGER ;
                     END ;

  DTA_RECORD       = RECORD { used by DOS 2.x filing calls }
                     used_by_dos   : ARRAY[1..21] OF BYTE ;
                     attribute     : BYTE ;
                     time          : INTEGER ;
                     date          : INTEGER ;
                     low_size      : INTEGER ;
                     high_size     : INTEGER ;
                     file_name     : FILE_NAME ;
                     END ;


-- 
<> Bob Geer        <> at decwrl!esunix!bgeer or utah-cs!esunix!bgeer  <>
<>    Bear-person  <> speaking only for myself, one of my many tricks <>
<> Salt Lake City, <> "We must strive to be more than we are, Lal."   <>
<>          Ootah  <>           -- Cmdr. Data, learning schmaltz      <>